Pump



atroz 1 w11 l July 2,V 1935.

E.. BENEDEK PUMP Filed March 16, 1931 5 Sheets-Sheet 2 Sin/vento@ July 2,1935- EBENEDEK 2,006,879

PUMP

Filed March 16, 1931 5 Sheets-Sheet 3 Fig.3

FLEX Emmi/ff;

E. BENEDEK July 2, 1935.

PUMP

File-@March 1e, 1951 5 sheets-sheet 4 Patented July 2, 1935 UNITED STATES vPATENT OFFICE PUDIP Elek Bcnedek, Milwaukee, Wis., assignor .to The Hydraulic Press- 'Manufacturing Company; Mount Gilead, Ohio, a corporation of Ohio Application March 16,1931, serial No. '522,895 1 claims. (ol. 10s- 37) '5 purpose ordinarily include a cylinder barrel and coacting impeller relatively .adjustable to vary the length of the pistonstrokes and to thereby regulate the rate of pump delivery by regulating pump displacement. In such pumps the relatively adjustable parts are subjected not only to severe hydraulic loads, but'also to severe mechanical loads, both of which increase directly as the hydraulic pressures increase and the combined effect of which is to impose a limit upon the hydraulic pressures which may be safely employed. One object of the present invention is the provision of a variable delivery multiple pistn pump capable of operation at pressures considerablyV higher than those employed in present commercial forms of variable displacement pumps. have accomplished by a novel combination and arrangement of .parts which does not require adjustment or variation in the piston stroke, so that the piston driving means and coacting parts may be more sturdily constructed and mounted to beti ter withstand the higher pressures, the variation in delivery being effected by auxiliary means adjustable to utilize variable portions piston stroke.

Another object is the provision in a multiple piston pump of valve means adjustably operable to utilize variable portions of each piston stroke and to bypass the liquid discharged from each pump cylinder during the remaining portion of each piston stroke.

Another object is the provision in a multiple piston pump of hydraulically balanced valve means for the purpose mentioned.

Other more specific objects and advantages will appear from the following description of an illustrative embodiment of the present invention. In the accompanying drawingsz- Figure 1 is a transverse sectional view of apump constructed in accordance with .the present invention. I'his view is taken on the section line I-I of Figs. 2 and 3. Fig. 2 is a longitudinal sectional view on the line2-2ofFig.1. A

`Il'lg. 3 is a horizontal sectional view on the line 3-3 of Fig. 1.

Fig. 4 is a.- sectional view, on a larger the valve mechanism'shown in Fig. 1.

Figs. -5 and 6 are sectional views on' the lines scale, of

l--l and 3-3 of Fig. 4, respectively.v

tionv I 0, supports a plurality of upright frames This I of each comprising a hollow base portion I 0, constituting a liquid reservoir, an intermediate upright portion II, and a cover portion I2. A large base casting I3, stationarily mounted inthe base porlo I4, which together provide a rigid support for a heavy crank shaft I5. In this instance the crank shaft is provided with a plurality of cony centric bearing disks I6 individually journalled in anti-friction bearings" mounted in the upper 1'5 ends of the frames I4. 1 The crank shaft I5 is driven by an extension shaft I8 formed integral with an end disk I6.

The several upright frames I4 also form guides for a series of slide blocks I9, vertically recipro- 20 cable therein and individually driven vfrom the crank shaft I5 through connecting rods 20. Each connecting rod shownterminates in a substantially ilat head 2I which bears against a large trunnion pin 22 rotatably seated within one 25 Aof'the blocks I9 and extending crosswise thereof .ing cylinder bore 26. In this instance each block 3*? I9v is socketed to receive the convex head 21 of its coacting plunger 25, the-head 21 being yieldably retained against the base of the socket by a spring 28 secured in place by a locking ring 29.

The severalv cylinder bores 26 in the base casting 40 I3 communicate, respectively, with transverse bores 30'.' which extend horizontally through thev casting. A chamber 3| in each bore 30 communicates with a channel 32, which extends'longitudinally 'of the casting I3 and communicates with 45 the pumop discharge pipe 33; and achamber 3 4 in each bore 30 communicates with another longitudinal channel 35 which communicatesl with;

. tween the'bore 26=and chamber 34,*so that with 55 the valve in the right extreme position of Fig. 1, bore 26 communicates with the discharge passage 32, and when the valve is'shifted into a left extreme'position, bore 26 communicates with the` take and discharge-.passages 34 and 32 is equally distributed about the end heads, 39 and 38, respectively, so that .each valve is also hydrostatically balanced radially. Each valve is thus freely movable irrespective of the degree of hydraulic pressure applied thereto, an important consideration in high pressure pumps of the type described. The several valves 31 are actuated in properly timed relation by appropriate means such as individual cams 40 on a cam shaft 4i, the cam shaft being driven from the crank shaft l5, at crank shaft speed, through an intermediate shaft 42 and suitable gearing 43 and 44. Eachvalve is provided at one end with a cam roller 45 which is held against its coacting cam by a spring 46 at the other end of the valve. e

The camshaft 4I is journalled in appropriate brackets 41 and 46 in which it is longitudinally shiftable to vary the effect of the several cams upon the respective valves. Although various means, either manual, lmechanical, or hydraulic,

' may be employed vfor eiecting'lengthwise adjustment of the cam shaft, I have disclosed a satisfactory hydraulic means for the purpose.` In this instance a reduced end 49 of the cam shaft is fitted in a bore 56 into which fluid pressure may be introduced through a pipe 5I to thereby shift the shaft toward the right (Fig. 3) against the resistance of a spring 52 which normally urges the shaft toward the left extr'eme position shown.

'I'he pressure uld for operating the piston 49 on the cam shaft may be supplied from any convenient source,'such aseby. connecting the pipe `I to the pressure outlet side' of the pump itself,

and regulating the Cadmission by any suitable type of valve.

The several cams 46 are of identical form but are set at dierent angles on thecam shaft cor-` responding to the dierent angular setting of the crank pins of the crank shaft I5. The right end of each cam (Fig. 3) is shaped to provide a single eccentric portion 53, as indicated in Figs. 1 and 7, so that, with the cam shaft in the position shown, its associated valve 31 provides communication between' the bore 26 and discharge passage 32 throughout the pressure'stroke of its associated plunger 25, and between the bore 26 and the intake passage 35 throughout the suction stroke of the plunger 25. Under that condition of operation the pump delivers a maximum volume. The opposite end of each cam is of double eccentric form, including a second eccentric portion 54, as indicated in Fig. '7, so that, when the cam shaft is shiftedfrom the position shown in Fig. 3 into a right extreme position, each cam acts upon its associated valve'in such manner as to retain thesame in a left extreme position throughout the pressure stroke as well as throughout the suction stroke of its associated plunger 25, so that all the'liquid which has entered the bore 25 from the intake passage 35,

during a suction stroke, is returned to the passage 35 during the succeeding discharge stroke. Under that condition pump delivery is zero.

That half of the periphery of each cam, which corresponds to the suction stroke of the pressure pump plunger 25, is of uniform contour throughout the length of the cam, so that irrespective of the lengthwise shifting thereof, the bore 26 is always open to the intake passage 35 throughout the suction stroke of the plunger. The other half of the periphery of each cam, which corresponds to the pressure stroke of the plunger, is of non-uniform contour and so designed as to cause the valve to open communication between the bore 26 and the discharge conduit 32 at various points in the pressure stroke of the plunger 25, dependent upon the lengthwise adjustment of the cam.

As previously pointed out, when the cam shaft 4I is in the position shown in Fig. 3, so that the cam rollers of the several valves follow the eccentric end portions 53 of their respective cams, each valve is caused to maintain communication between the bore 26 and discharge passage 32 throughout the pressure stroke of the corresponding plunger 25, and the pump then delivers a maximum volume. Then as the cam shaft is shifted toward the right until each cam'roller contacts with its cam in a plane corresponding to the plane of section line 8 8, a narrow lobe 55 (Fig. 8) on each cam causes its coacting valve to eiect communication between the corresponding bore 26 and intake passage 35 during the early portion of the pressure stroke of the corresponding plunger 25, so that during that portion of the stroke liquid escapes from the bore 26 back into the intake passage 35, and thereafter the valve is promptly shifted to effect communication between the bore 26 and the discharge passage 35. The volume of liquid discharged into the passage is thus somewhat reduced.

'As indicated 1n Figs. 9 and 1o,the1obe 55 of each cam becomes increasingly wider as it extends toward and finally merges into the second eccen-A tric 54, so that as the cam shaft is shifted further toward the right (Fig. 3) communication between each bore 26 and discharge passage A32 is delayed to thereby further reduce the volume of liquid discharged by the pump.

The volume of discharge from the pump may thus be varied from maximum to zero by shifting the cam shaft 4I toward the right from the position shown in Fig. 3 to a position in which the several cam rollers follow the left ends of their respective cams.

lThe intake passage 35 communicates through a passage 55 with a low pressure relief valve 51 of a well known type, comprising a hollow element 56 yieldably retained against its seat by a spring 56. A ball type check valve 59' cooperates with a port 66 in the element 53 to permit free passage of liquid therethrough from thebody of liquid in the base Ill of the housing into the intake passage 35.

It will be noted that each of the several valves 31, in shifting from one extreme position to the other, passes through the intermediate position of Fig. 4 in which it blocks communication between the bore 26 and both the intake passage 35 and the discharge passage 32. In order to avoid theshocks and strains that would ordinarily result from'a trapping of liquid in each bore 25 during the passing of each valve through this intermediate position, particularly as this commonly occurs duringa pressure stroke of lengthwise reciprocation in a bore 62 formed in the end member of each valve. \The plunger 6| is yieldably retained in the-left end of the bore by a light spring 63, andalso by pressure i transmitted from the discharge passage 32 to the right end thereof through gashes 64 in the plunger and ports 65 in the valve. The left end of the plunger 6l is also exposed to the pressure in the -bore 26 through ports 66 and a passage 61 in the valve. A passage 66 in the plunger 6I communicates with the passage 61 and also with radial passages 69 in the plunger'. The arrangement is such that as the pressure in'bore 26 increases suillciently to overcome the pressure againstthe rightend'of the plunger 6I, the plunger 6`wi1l shift to the right (Fig, 4) until radial passages 69 communicate with ports 65, whereupon liquid from the bore 26 'will pass into the discharge passage 32.

- In orde to guard against too rapid a change in the degree of pressure within the bore 26 the inner end I of the portion 39 of each valve 31l is preferably groovedfas indicated at 10, so as to effect a gradual cutting oi of communication between the intakepassage 35and bore 26, as the valve moves from a left extreme position to the intermediat position of Fig. 4, and so as to effect a gradual ning of communication betweenv those parts during movement of the valve in the opposite direction.

Various changes may be made in the embodiment of the 'invention hereinabove specifically described without departing from or sacrificing the invention as defined in the appended claims.

I claim:-

1. Ina pump, the combination of acylinder, an intake passage, a discharge passage, a movable valve effective in one position to'eii'ect communication between said cylinder and said intake passage and eil'ective in another position to effect communication between said cylinder and said discharge passage, and a pressure responsive relief device contained within said valve and adapted to pass liquid into said discharge passasge upon the attainment of a predetermined pressure in said cylinder irrespective of the position of said valve. f

2. In a pump, the combination of a cylinder, an intake passage, a discharge passage, a movable valve effective-inone position to effect communication between said cylinder and said intake .passage and efiective'in another position to effect l'communication between said cylinder and said discharge passage, and a pressure responsive 1relief device contained withinsaid valve and adapted to pass liquid into said discharge passage upon the attainment of a predetermined pressure in said cylinder irrespective of. the position of said valve, said valve consisting of a body portion and spaced heads flxedly mounted upon said body. portion.

' 3.- In a pump, the combination of a cylinder, an intake passage, a discharge passage, .a movable valve effective in one position to effect communication between said cylinder and said intake passage and eiective in anotherl position to effect communication between said cylinder and said discharge passage, and a pressure responsive re` lief device contained within said valve and adapted to pass liquid into said discharge passage upon. the attainment'bf a predetermined pressurein" said cylinder irrespective of the position of said valve, said valve' having a bore therein, andaid relief device including a member movably mounted in said bore and yielding `means urging said lmovable member into a position adapted to close communication between said cylinderI ands'aid discharge passage. i'

4. In a variable delivery pump the combination of a plurality of cylinders, -an intake passage, a discharge passage, valve mechanism controlling communication between said cylinders and said intake and discharge passages, p lungers working in said cylinders, driving means for said'plungers,

means driven in timed relation with said driving' of a plurality of cylinders, an intake passage, a

discharge passage, individual valves for the respective cylinders controlling communication between said cylinders and said intake and discharge passages, plungers working in said cylinder's, means for operating said valves, said last named -means being adjustable to vary pump delivery, and pressure responsive means contained `in said valves and associated with each cylinder for admitting liquid therefrom to said discharge passage irrespective of the position of said valve mechanism.

6, In a pump the combination of a cylinder, anY

intake passage, a discharge passage, a longitudinally reciprocable valve effective in one position to effect communication between said cylinder a`nd said intake passage and effective in another position to eilect communication be" tween said cylinder and said discharge passage, said valve being effective in anintermediate position to block communication between said cylinder and said passages, and pressure responsive means' within said valve for admitting liquid from said cylinder to said discharge passage.

7. In a pump, the combination of a cylinder, an intake passage, a discharge passage, a movable valve effective in one position to effect communication between said cylinder` and said intake passage and effective in another position to effect communication between said cylinder and said discharge passage, and a pressure responsive relief device contained within said valve and adapted to -pass'liquid into said discharge passage upon the attainment of a predetermined pressure in said cylinder irrespective of the position of said v'alve, said valve consisting of a body portion and spaced heads flxedly mounted upon sai portion, said valve having a bore therein, a said relief device including a member-movably mounted in vsaid bore and yielding me urging said movable member into a position apted to close communication between said ey' der and said discharge passage.

' ELEK BENEDEK.

bOdY c5 

